mtjller



- 4 Sheets--Sheet 1.

R. MULLER.

Patented April 12,1881.

'Gas Generating Furnace.

(No Model.)

No.240,l65.

(If/y IN VBNTOR a%%% ATTORNEY R, WASHINGTON D. 0.

N4 PETERS, PHOTQLXTHOGRAPHE WITNESSES 4 Sheets-Sheet 2.

(No Model.)

B. M't'ILLER. Gas Generating Furnace.

Nd.240,l65.

Patented April 12,1881.

. t v A ,W 1 fi m 4 4! h a Mil 7 v a 4.

v I I m INVENTOR WITNE SES:

ATTORNEY P MOTO-Llmcammizi. WASHINGTON u (A (No Mqdel.) 4 Sheets-Sheeta.

, R MULLER.

Gas Generating Furnace. No.-240,165. Patented April 12,1881.

' mun $11 ATTORNEY WITNESSES:

a /Y7 I 4 Sheets-Sheet 4.

(NoModeL) R. MULLER.

Gas Genera ting Furnace.

Patented April-1 2,

WITNESSES N. PEriRs. PHOTO LXTHOGRAPNEIL wAsnmGmN, 0 c,

. UNITED STATES PATENT OFFICE.

RUDOLF MULLER, F BERLIN, GERMANY.

GAS-GENERATING FURNACE.

SPECIFICATION forming part of Letters Patent No. 240,165, dated April12, 1881.

Application filed April 1, 1880. (No model) i To all whom it mayconcern:

Be it known that I, RUDOLF :MljLLER, of the city of Berlin, in theKingdom of Prussia,

German Empire, have invented Improvements in Gas-Generating Furnaces, ofwhich the following is a specification.

This invention relates to improvements in gas-generating furnaceswithout special gasgenerators, and more especially to improvero ments inthe construction of the kilns, ovens,

850., for which I have heretofore filed an application for LettersPatent, under date of February 9, 1880, and No. 2,406.

This invention is designed to produce a more 1 5 perfect and economicalcombustion of the fuel, by obviating the loss of heat incidental to im-.perfect combustion in the common grate-furnaces, and also the loss ofheat caused by the drafts of the chimneys.

It may be prennsed here that the most perfect combustion of fuelhitherto known is produced by the gas-generating furnaces withseparategenerators. Thesefurnaces, however,

- consistof several separate parts of a fire-place 2 5 proper, of agas-generator, and of lines, and

sometimes, in addition thereto, of a generator or an apparatus by whichthe fire-gases and the air required for combustion are heated up tohigher degree of temperature preparatory 0 to their combustion. In thesefurnaces the fuel is fed" into a shaft and burned in connection with astrong air-current, by which a complete combustion is obtained. Thecarbonic acid developed by the combustion takes up carbon in the upperlayers of fuel and forms carbonic oxide. Simultaneously therewithcarbureted hydrogen is formed, and some portion of the water containedin the fuel is decomposed by the heat. The result is, that thecombustible 4o gases are finally drawn off to the generator at a lowertemperature, owing to the transformations which take place. Another partof the heat is lost by radiation of the walls of the generator andfines, so that it is necessary to reheat the gas to a higher temperaturein a regenerator, which is interposed between the generator and thespace where the gases are to be burned. There a high degree of heat isobtained without special devices for the combustion of the gas, and thefuel thereby utilized in the most complete manner.

Various systems of furnaces with generators have been devised, which,though having greater or less theoretical value, are for practicalpurposes too com plicated and not adapted 5 5 for a great number ofapplications.

My invention has for its object to dispense with the separategas-generators described, and to generate carbonic-oxide gas and otherproducts produced by a coking of the fuel, and to produce the combustionof the gas in the same space, but in a higher portion or zone of thesame, by the introduction of air which has been heated up in its passagethrough proper channels. The incombustible gases are drawn 6 off to theatmosphere by separate channels without employing a chimney, whichlatter is dispensed with in my construction. This method of burning thegases which are generated in the same space without a special generatorI have heretofore to some extent described in my application filedFebruary 9, 1880.

In this application I intend to describe the adaptation of-iny systemfor porcelain and other ovens, for the economical heating of stoves,steam-boilers, and other technical applications.

The following elements occur in every specific application of mysystemof heating:

The gas-generating part consists of a boxshaped open fire-place withgrate and ash-pit, which latter can be hermetically closed. The door ofthe ash-pit is only opened when the \tire is started, so as to obtainthe heat necessary for the proper coking of the next layer of fuel andthe generation of gas. As soon as this heat is obtained, the ash-pitdooris closed and a small slide in the same opened, so that onlysufficient air is admitted to keep the fuel 0 in its coking state forthe formation of the firegases. Owing to the small amount of airrequired, the gratemay be constructed in a different manner from thegrates commonly employedin furnaces. Theintersticesbetweenthe 5grate-bars have to be only large enough to admit the removal of theashes, as no clinkers are formed, owing to the comparatively lowtemperature. The open spaces can therefore be made small and the topsurface of the bars large. The grate-bars can even be made of badnon-conductors of heat-such as fire-clay,

or fire-clay mixed with coal-dust--Which gratebars are soon at red heat,and assist thereby in the generation of gas. Above the grate is anopening, which is closed by a regulatingslide, and above this slide adoor for supplying the fuel, which door may also be hermeti-- callyclosed.

As soon as the fire is started, the ash-pit door is closed with theexception of its slide, and then the bottom layer of burniu g fuelcovered by a layer of dry fuel, after which the supply-door is alsoclosed. At first a lively development of carbureted hydrogen takes placeuntil all the water in the fuel is expelled. Then the formation ofcarbonic-oxide gas begins, the required oxygen being partly taken fromthe airin thefire-place and partly drawn in through the regulating-slideimmediately above the grate. The combustible gases thus obtained areburned in the higher parts of the furnace after they have mingled withthe air supplied by separate channels. The channels are so disposed thatthe combustion in any part of the furnace can be easily regulated, andare provided with means for closing them tightly whenever required. Achannel above the supply-door serves forlooking in and supervising thecombustion.

The next essential feature of my system of heating is the drawing off ofthe incombustible fire-gases, which are generally collected near thebottom of the fire-place and mostly close to the walls, as here theleast interruptions take place. These gases consist of aq ueous vapors,carbonic acid, nitrogen, &c., which are heavier than the atmosphericair. To draw them off, channels extend in the furnace-walls from thebottom of the furnace toward the top and open into the air. All theheavy gases pass off through these channels, so that chimneys can bedispensed with, as there is no need ofa draft in this system of heating.To still more facilitate this drawing off of the heavy gases, thechannels may be connected with a kind of gutter below the bottom of thefurnace.

In addition to the means employed for getting rid of the heavy gasesthere have to be channels for the removal of the lighter incombustiblegases from the top part of the furnace. These channels begin at. thehighest part of the top, are extended downward in the walls, andarranged to open into one of the channels through which the heavy gasesare drawn ofl. These downward-extending channels are provided with aslide for being opened or closed. The light gases are drawn off bysuction as soon as the slide is opened, at any time when the dullburning of the flame indicates the presence of too great a quantity ofgases. As soon as the flame is bright'and clear the slide is closed.This system is applicable to every furnace, and can be used withfurnaces already erected without great changes. Itis, however, bestadapted for furnaces having an open fire-place and no fiues--such asbrick'and lime kilns, porcelain, drying, and other ovens and also forsteam-boiler furnaces, as will appear more fully hereinafter.

In the accompanying drawings, which illustrate my invention and to whichreference is made, Figure 1 represents a sectional side elevation of abrick-kiln constructed according to my improved system. Figs. 2 and 3are, respectively, a horizontal and a vertical transverse section of thekiln on lineazac, Fig. 1, and y y, Fig. 2. Fig. 4 is a detail sectionthrough one of the fire-places, showingthe disposition of theair-channels. Fig.5 is a horizontal section of a brick-kiln divided bypartitions into chambers, and constructed according to my system. Fig. 6is a vertical central section of a limekiln with my improvements. Fig. 7is a sectional elevation of a porcelainoven. Figs. 8 and 9 are verticallongitudinal and transverse sections of a heating-stove. Fig. 10 is avertical longitudinal section of a bakers oven, all constructedaccording to my system; and Figs. 1.1, 12, and 13 are verticallongitudinal and transverse sections and a front view of steam-boilerwith a furnace arranged with my improvements.

Similar letters of reference indicate corresponding parts.

Referring to the drawings, a a are the fireplaces, each of which isarranged with an opening, b,'for supplying the fuel. The supplyopeningbis divided, by a short horizontal partition, f, into two channels, thelower and smaller of which is closed by a double slide, 9, while theupper and larger is closed by the door 01. The double slide 1 serves toadmit the air for the proper coking of the fuelin the fire-place, andfor the generation of the gases from the layer of fuel above the bottomlayer.

rro'

In Fig. 1 the slide 9 and door 61 are shown on one fire-place only, butleft off in the remaining ones. The ash-pit h is closed by a door, I,having a small opening and slide, 2'.

At each side of the fire-places a a is arranged a group of openings,which communicate with channels m and m, through which the air requiredfor the combustion of the gases is conducted into the interior space ofthe kiln. They extend parallel to the fire-places back to the rear wallor to the partition-wall of the kiln, then upward in the wall, wherethey open to the interior of the kiln at different heights, theair-channels m being run up higher than the channels m, as shown clearlyin detail in Fig. 4.

Converging channels it n extend from both sides of the supply-opening btoward the rear part of the fire-place a, and open there into the same.A second set of channels, a, above the channels a run first inhorizontal direction, then upward in vertical direction, and open intothe kiln at about the height of the channels m, as shown in Figs. 1 and3. Above the supply-opening is arranged a horizontal channel,19, whichserves to control the progress of the fire. All the channels can behermetically closed by slides or covers in the same manner as the doorsand slides g and i. The channels it serve, mainly, for the purpose ofsupplyin g the air necessary for the ignition of the gases generated inthe upper part of the kiln. They need not be made as large as the otherair-channels. All thechannels can either be formed in the brick walls orbe made of pipes of clay or other material. By this arrangement ofair-supply channels the first or direct firing, which is necessary todry the green bricks during the first part of the burning process, canbe kept up, the gases of combustion being conducted off directly throughthe top channels, 0 0. WVhen the bricks have been exposed fortwenty-four to forty-eight hours to the direct firing they can beexposed to a greater heat, and the generation of gas is commenced byclosing first the top draft-holes, 0, by means of clay plugs. Theproducts of combustion are now drawn off through the channels 1", whichbegin close to the bottom of the kiln, one being arranged intermediatelybetween the fire-places in the side walls, and two in each of the endwalls. These channels extend upward and pass out through the top of thekiln, as shown in Fig. 1. The heavy products of combustion, which settleat the bottom, are thus drawn off through the channels 1", while thelight products pass through the channels 8 s, which begin in the top ofthe kiln vertically above each fire-place and run downward, as shown inFig. 3, being finally connected to one of the channels 1". Each channelscan be shut off from the channel r by a slide, t. (Shown in Figs. 1 and3.) These slides t are closed after the top draftholes, 0, have beenplugged. The ash-pit doors are also closed; but their slides are openedsuffieiently to keep the fuel in the tire-place aglow. A layer of fuelis now placed on the burning bottom layer, after which thesupply-opening d and the slides g are closed. A lively generation of gasnow takes plaoe,a sufiicientquantity of air being supplied through thechannels m m and n n to maintain a steady and complete combustion of thegases. As the gases are burned as soon as generated and mingled with airwhich is heated up in its passage through the channels, a hightemperature is obtained. As the airsupply openings are properlyregulated for the perfect combustion of the gases, there is no draft inthe kiln, and all the heavy products of combustion, including thenitrogen of the air, settle at the bottom of the kiln, where they aredrawn ofl' through the channels 1'. These gases heat up the walls of thekiln, they giving up all their heat and passing out into the atmosphereat a low temperature, consisting mainly of carbonic-acid gas andnitrogen.

After the fuel has given off all its gases, it is burned by admitting alimited supply of air. This is accomplished by opening the slides 9below the supply-door. The carbonic-acid gas which is thereby formed isburned in the same manner as the gases before obtained. The slide of theash-pit door can, for this purpose, be somewhat opened. Afterthree-quarters of an hour or an hour the fuel is entirely burned, and anew layer is supplied, and the process first described repeated. In casethe layer of cokes on the grate becomes too high, the ashpit door isopened for some time, and aperfect combustion of the cokes obtained.until the layer of cokes is reduced to its normal thick ness of fromeight to twelve centimeters. After three or four hours there will benoticed through the controlling-channel p dark spots in the gas, whichbecome more and more numerous, and change finally into streaks, untilthe tire seems to disappear entirely and the flame, mixed with smoke,appears in the controlling-channel. This is caused by the increase ofthe lightproducts of combustion in the upper part of the kiln. whichforce the heavier gases downward. The slides tare now opened, and thelight gases drawn off with great velocity through the channels .9 and1'. When all the light gases are drawn off, the flame resumes itsbrightness, and theslides t are closed again. In such kilns or ovens, inwhich the construction of the inclinedchannels 25 would be toodifficult, the gases can be drawn off directly through top channels provided with covers t, which are operated by a system of levers, t, orotherwise, from below.

I have described fully the working of my system of heating in connectionwith a brickkiln; but it is evident that the essential features employedcan also be used for other kilns. I will describe a few applications ofthe same.

In Fig. 5 a brick-kiln with eight chambers is shown, in which theair-entrance channels are shown, but. the discharge-channels areomitted. The latter may be arranged either in the manner described orthe gases may be drawn off from one chamber into the other, so as to beutilized in the next chamber. In the latter case the partition-walls arearranged just above the bottom, with communicating channels and slides,so that the gases can be drawn from one chamber into the next adjoiningone, in connection with the draft-channels for the preparatory heatingup of the green bricks or-other material in this chamber, and so onsuccessively. In Fig. 6 the same system is applied to a limekiln,inwhich all the airsupply and gas-discharge channels are shown, asbefore described. Fig. 7 shows a porcelain-oven arranged in similarmanner, but withaforward-projectingfire-place. Thechannels are, however,for the sake of greater clearness, not all shown. Figs. 8 and 9 show theapplication of the same principle to a common heating-stove, and Fig. 10to a bakers oven, while the application of the same to the furnaces ofsteam-boilers is shown in Figs. 11, 12, and 13. In Fig. 11 thesteam-boiler was formerly arranged with an interior furnace; but as sucha furnace is not adapted for direct gas-burnin g without generator, thefurnace has been placed in front of the boiler. For conducting oi theheavy products of combustion from the neighborhood of the grate, thetubes 1' are employed, which are separated from the grate a by means ofabntments. Fig. 13 represents the fire-doors d, the ash pit doors I,with the slides 2', and the slide g, which are Worked in the same manneras the analogous parts of the kiln before described. The gases aregenerated in the same manner and burned in part above the tire, butmainly in the lines, into which the air is introduced, in heated state,through channels 1". The combustion takes place slowly and steadily, andrequires no chimney, as no strong draft is required for carrying off thegases of combustion and keeping up the fire. In cases where the chimneyhas been used the same has to be nearly entirely closed by the damper.The remaining gases of combustion are drawn off through thepartly-opened damper of the chimney or through special eXit-channels.Besides the complete combustion of and economy in fuel, this system, asadapted to steam-boilers, has the advantage that when the boiler isstopped by closing all the channels and openings, a sufficiently hightemperature is retained in the furnace to continue the generation of gasand the burning of the same as soon as the boiler is required for workagain. The work of the boiler can be interrupted up to twenty-fourhours, which is of considerable advantage in many cases.

Having thus described my invention, I claim as new, and desire to secureby Letters Patent 1. The method herein described of heating kilns,ovens, steam-boilers, 800., without a separate gas-generator, consistingin generating carbonic-oxide gas from a layer of fuel superposed on acoking layer of fuel, mingling the same with heated air, and burning thegas and air mixture above the fuel, and finally drawin g off the heavygases through channels communicating directly with the outer air and thelight gases through circulating-channels communicating with the channelsfor the heavy gases, as set forth.

2. The combination of a kiln, oven, or furv nace havingdischarge-channels for the heavy products of combustion, said channelsextend-

